Static eliminator



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Jan. 13, 1931.

STATIC ELlMINATOE 2 Sheets-Sheet 1 'iriginal Filad Nov. 1925 GZzlverLeeEeZaM INVENTOR M /4 BY -ATTORNEY WITNESS:

15m. 13, 1931. L, RICHARDS 1339:1192

STATIC ELIMINATOR Original Filed Nov. 3, 1926 2 Sheets-Sheet 2 WITNESS:

n V V. a cess, toeliminate from radio receiving appa- Patented Jan. 13, 1931 y v UNITED STATES P TENTOFFICEQ OLIVER LEE nrcminns, or cusnrneanims F Application filed November 3, 1926, Serial It'd. 146,004. Renewed May 31, 1930.

This invention relatesto static eliminating devices for use in radio reception and has for its object the provision of a novel device by. means of which the various objectionable noises incidental to static disturbances and various varieties of local interference may be entirely eliminated fromthe reception of broadcast musicand the like. b

It is well known that various attempts have been made, withrather indifferent sucjratus the undesired impulses of current which,rwhen amplified, create the character-' isticrattling, rapping, and otherwise objectionable sounds emitted from loudspeakers. However, thus far it has seemed tobe practically impossible to filter such impulses out of the circuit and it is for this reason that I have designed thepresent invention, which has for its principalobject a mode and means ioperating in conjunction with a sensitive receiving instrument asa telephonereceiver,

capable of reproducing only" the desirable sounds of transmission. My system depends on the well known.- principle that strings or.

othersharply tuned harmonic resonators will I respond only to the frequency or. pitch char acteris'tic of certain notes, the theory, as applied to the present invention, being that as thereare noharmonic devices capable of producing sound corresponding tostatic interferences and the like, there will bfizno reproduction in soundof such interference, the undesirable vibrationsbeing consequently filtered out of: the receiving system,.,or, loud speaker.

An important object .of the invention is to provide :a static eliminating device-of this character adapted to. be interposedbetween the responding output, namely, a telephone, ofa radio receiving set and-a suitable loud speaker with microphone and battery to-amplify the weak currents delivered by. the re-f ceiving antenna. L i i Another: object is the PI'OVlSlOll ofadevlce of. this character provided with means whereby all ofthe sounds emitted from the output of the radioreceiving' set may be listened to by the operator in tuning, means being pro- .yided Where only thefiltered vibrations will 1 Figure 2. is across section have i an advantage in -preferred.

be operative on the final receiver after a.

certain selected station has been tuned in. 1 "j Another object is the provision ofa structure or apparatus of this character which will be simple and inexpensiveto manufacture, easy to control and operate,;positive.in

action, efficient, and-durable in service, and

will be a muchneededimprovementin.the T accompanying drawing-sin which :1.

. Figure l'is a sectional-viewthrougli the complete apparatus, the

diagranr of the, cir- CtlllTEllSO being (llSClOSGCl;

' taken on the line 2-2 of Figure 1.-

Figure 3 is a longitudinal section taken on the line8-3 of Figure 1.

Referring more mediation .ai aiamgh' Figure 4 isan elevation" showing the com-1f particularly to thetdrawings, I have shown the dBVICG asicomprlsing y a suitable casing 10 which is best hermeti cally sealed and rendered soundllproof;

Mounted within one end ofthis casing,as for" instance upon a-bracket 11 or the like, is a telephone receiver 12 constituting the output 7 I of a radio receiving set, containing tuning means and rectifying devices as crystals or casing- 10 is a frame or sounding board-1 4 ferent lengthssoas to be capable of being tuned to different pitches. Obviously, any

ordinary orfpreferred type of tuning pins may be employed though-such are not shown in detail as-they really constitute no partof the present inventionand can be anything desired, nor need the harmonic elements necessarily be stretched strings as any type of resonator mightbe used; strings, however, compactness and a re one end the strings are vacuum lamps. ,Mounted withinthebiox or' Y fabar 16 ca able of compounding all the harmonic vi rations of the several strings and reproducingthe composite efiect thereof.

Suitably mounted upon the end of the casing opposite that where the telephone re- 16 and having itsother end connected by a link 21 with the center of. a diaphragm 22 suitably'secured, as hi it cap 23; across the open end of a sound box 24 with which is connected a conduit 25;

The numeral 26 designates conduit which "is connected with one sideof the casing 10 in anyfisuitable manner and whichis shown -as terminating in 411T '27 having one branch ctinn'ected with the conduitaindhaving its 7 other branch connected with amicr'ophone 28 of Mimier preferred type, The element 256s verysiinilar to the swingingnrm vided a simply-'jconstriicteddevice for the ofanordin'ary commercial phonograph. For

- a mechanical supportingpurposes,"use,m2iy be 1 made of a brace 29 connected with the conduit urernber26 and with the sound box 24, thougfiobviously, itshould be understood that "or g ll-cf the details of construction of thesefiparts inay varied wide limit; t I I t "As mehtioned'above', the type of micro phoheis immaterial and it" st ewn as equipped with binding posts or othenterminal members 30 with which are connected cendfiCtdrS 31 intu'rn connected witha loud speaker 32, of any desired type; a suitable sourceof current 33 bcingintferp'osed foreffecting amplification,

The conduit 26 is prov1ded, 'ata point preferablynearthe casing, with enen largedportione whi'ch of course connnilnicateswith 3 the interior of the casing and-within which is "mounted af dlsk fa-Ive,- or vane 35," or

1 equivalent type carried by a rod '36eq uipped yiithfa, dial ,and l mob 37-=and preferably *yiuumaled' throughj a. suitable. hearing or bracket 38. The valve actsto'shu'tfoff entirely or only partly the air communication through "the soune'euctee.

In' 'the operation of 'the device,-

will of coursebefga pperent weenie sound emitted frofhthe telephone receiver 1'2 w-ill produce sympathetic vibration of'the strings 15, the composite or combined vibrations 'lji'eing trans mittedtothe bar 15 and then e unmet the li k flo en le; lever" 19. jahai lifnli 21 to the eia hmgm 22; Wiener; course corresponds were the vibr rtionif'lhe strings are or e I =1ap geeneug'hi iniber to respond hari'rroi1icsllj to all musical fre uencies necessary to lit) sleet a mealtime {tune of eharact'e'eis cie timbre inthe gamut of the voice'orfmusicl Thesound waves set by the diaphragm impisgin against the iaphragm of the microphone 28 will operate to vary the resistance to 'stressesue eeeaucarmrest from the that theoperato'r grasp and tufrn the knob tors 31 and loud speaker 32. The variations and'dial 37 to open the Valve 35, whereupon athe total; ensemble, of sounds generated within the' casing 10' will pass directly 1 through the conduit26 to the microphone and be reproduced at the loud speaker. When,

however; it? is not desiredfito llisten to announcements md when itis desired to filter Loirt static disturbances, the valve 35 should he closed, whereupon? the only soundsreproduceil will bethose set up by thesj'mpathetic Thus, it wi purpose specifiedand one which will cfllcientl y p'erform al1*th functions for which it is intended. ObviOusIYQftlic devicewi'll be a great benefit 'to the' public inasmuch-as the qu'nlity of the reproduction of ;broadcast 'rnusichrid the like will be greatly improved. It isflreirlly believed thattheconstruction, operation and edvantagesfwill be readily apparentto oh'e skilled in-thef m withoutjfurthen explanation;

EWhiIe l hav'eshown and described the preerred embodimentof the invention, it should be understood that I reserve theright tonlake f'such cha nges in the form, construction and ar angement ofpart's, 'as 'will'not depart from the spirit of the invention).- the s'c'opeof the snbjoine'd claims i p Havin thus described"the invention, I claimzg 1. In ;oon'1binatioh,

Cally with the some vibrations einitted iroln a telepl'lonc receiver-f adapftedfto be con nectcd with. the output from :t 'acl io receiving,apparatus,- a series of vibraf tory elements adapted tovibrate sympathetivibrations of the strings 15 and which will be e apure re roduction; f-

llbe apparent that I have prothe telephone receiver, a microphone' cnd a loud speskerj connected f in series therewith, and'rneans for transmitting thecomposite vibrations of said vibratory elements to" the 1 microphone, said means comprising sensin a conduit connected withthe casing and lead ing to the" microphone; a diaphragm mounted within asing, and mechje'nical conneccan between thedipahragm and ndv tre- Ififiiflevice er the character dee ed,

.'a' casing; a telephone receiver mounted there-d in and iadapted to be connectedfwiththe-out put from a radio receiving appatmtus; a

tigers; stretchedalcngth'sorrnding boerd,

said strings vibrating sympathetically with the sound vibrations emitted from the tele phone receiver, a microphone, a sound box connected with the microphone and having a diaphragm, and mechanical connections between said bar and the diaphragm for vibrating the latter. 7

3. In a device of the character described, a casing, a telephone receiver mounted therein and adapted to be connected with the output from a radio receiving apparatus, a sounding board Within the casing, a plurality of strings stretched along the sounding board, a bar to which one end of all the strings are connected, whereby to vibrate in accordance with the composite vibrations of the strings, said strings vibrating sympathetically with the sound vibrations emitted from the telephone receiver, a microphone, a sound box connected with the microphone and having a diaphragm, and mechanical connections between said bar and the diaphragm for vibrating the latter, a conduitcommunicating with the casing and leading directly to the microphone, and means for'opening and closing said last named conduit at Wlll.

4. In a device of the character described,

a casing, a telephone receiver mounted therein and adapted to be connected with the output from a radio receiving apparatus, a sounding board within the casing, a plurality of strings stretched along the sounding board,

a bar to which one end of all the strings are connected, whereby to vibrate in accordance with the composite vibrations of the strings, said strings vibrating sympathetically with the sound vibrations emitted from the telephone receiver, a microphone, a sound box connected with the microphone and having a diaphragm, and mechanical connections between said bar and diaphragm for vibrating the latter, a conduit communicating with the casing and leadlng directly to the mlcrophone,

and meansfor opening and closing said last named conduit at will, comprising a valve interposed therein, and means for controlling the valve.

In testimony whereof I aflixmy signature.

OLIVER LEE RICHARDS. 

